If your goal is to protect the forum from bots, then I recommend trying the Antibot module. This module uses original and newer bot detection technology than older anti-spam modules. It secretly monitors whether the user who posts a comment is using a keyboard or a touch screen and, in the absence of such, blocks access to the comment form (and any other forms). The form is also blocked if the visitor does not interpret the JavaScript code used by this module. Thus, the module very efficiently eliminates bots that do not use a keyboard, touch screen and JavaScript, and at the same time its action is imperceptible to human visitors.
However, this will not protect you from malicious human visitors, for whom another solution must be sought, and it would probably enable protection against a reasoned analysis of the content of the post.
If your goal is to protect the forum from bots, then I recommend trying the Antibot module. This module uses original and newer bot detection technology than older anti-spam modules. It secretly monitors whether the user who posts a comment is using a keyboard or a touch screen and, in the absence of such, blocks access to the comment form (and any other forms). The form is also blocked if the visitor does not interpret the JavaScript code used by this module. Thus, the module very efficiently eliminates bots that do not use a keyboard, touch screen and JavaScript, and at the same time its action is imperceptible to human visitors.
However, this will not protect you from malicious human visitors, for whom another solution must be sought, and it would probably enable protection against a reasoned analysis of the content of the post.